os fractures - ALL OF NATS Flashcards
1
Q
- What does reduction mean?
A
Aligns bone ends anatomically, recreates normal anatomy
2
Q
- What does fixation mean?
A
Prevents movement of bone margins whilst healing occurs
3
Q
- What are the types of mandibular fracture?
A
Simple, compound, comminuted, greenstick, pathological
4
Q
- What are the possible sites of mandibular fractures?
A
Dento-alveolar, condylar, coronoid, ramus, angle, body, parasymphysis, symphysis, Guardsman’s, Bucket Handle
5
Q
- What is Champy’s principle?
A
Miniplate osteosynthesis = placement of plate along ‘so called’ ideal line of osteosynthesis to counteract distraction forces that occur along fracture line; load sharing
6
Q
- What is the possible pulmonary consideration of reduction management for mandibular fractures?
A
If pt. has reflux/GI issues then stomach contents can go into lungs
7
Q
- What is the commonest type of fracture?
A
Condylar
8
Q
What is this?
A
- Bridal (fracture wedding :))) wire
9
Q
- What does a bridal wire do?
A
Pulls fracture at superior margin, removed after plates placement
10
Q
What is this?
A
Leonard buttons
11
Q
- What do Leonard buttons do?
A
Aligns the fracture
12
Q
- What are Ericht Arch Bars?
A
Preformed bars cut to size, wires to every tooth with ortho elastic bands
13
Q
- What is the problem with Ericht Arch Bars?
A
Compromised gingival health
14
Q
- What are IMF screws?
A
Cortical screws, rigid wire IMF
15
Q
- What should you avoid when using IMF screws and why?
Avoid canine and 1st pre-molar apices because of mental bundle
A
Avoid canine and 1st pre-molar apices because of mental bundle
16
Q
- What is closed reduction and fixation w/ arch bars?
Custom made CoCr arch bars, wax bite of occlusion made
A
Custom made CoCr arch bars, wax bite of occlusion made
17
Q
- What is closed reduction and fixation with cast cap splints?
A
Not used anymore – imps → CoCr splints → cement on teeth
18
Q
- What should be used for edentulous fractures and how?
A
Gunning splints; open reduction done nowadays instead of GS, wired for up to 6 weeks
19
Q
- What is the benefit of EO open reduction?
A
Less effect on vascularity of bone → facilitating healing
20
Q
- What kind of problems are associated with edentulous fractures?
A
Atrophic → poorly vascularised → poor healing; less bones available to reduce/fix; lack of landmarks
21
Q
- Which side does the pt. deviate to when they have a condylar fracture? Why?
A
Side of the fracture as the length of the condyle is shortened; there will be premature contact on the fracture side and an open bite on the normal side
22
Q
- How do you test for altered sensation?
A
Soft touch – cotton roll, sharp – sharp probe
23
Q
- What are the 4 major parts of the zygomatic bone?
A
Frontal, medial, maxillary, temporal
24
Q
- What is type 1 of the classification of the zygomatic fracture?
A
No significant displacement
25
1. What is type 2 of the classification of the zygomatic fracture?
Fracture of zygomatic arch
26
1. What is type 3 of the classification of the zygomatic fracture?
Rotation around vertical axis – internally, externally
27
1. What is type 4 of the classification of the zygomatic fracture?
Rotation around the longitudinal axis
28
1. What is type 5 of the classification of the zygomatic fracture?
Displacement en bloc – medially, inferiorly
29
1. What is type 6 of the classification of the zygomatic fracture?
Displacement of the orbit-antral part – inferiorly, superiorly
30
1. What is type 7 of the classification of the zygomatic fracture?
Displacement of orbital rim segments
31
1. What is type 8 of the classification of the zygomatic fracture?
Complex comminuted fractures
32
1. What are the advantages of ORIF?
Improves alignment, fixation of zygomaticomaxillary buttress 🡪 provides vertical support; Orbital rim exposure allows inspection of orbital floor, inspection of fracture sites prior to closure
33
1. When should you explore the orbital floor?
When defects \>5mm on CT scan, severe displacement, comminution, soft tissue entrapment with limited upward gaze, orbital content herniation into maxillary sinus
34
1. When should you do 2-point fixation of zygomatic fractures?
When fracture is minimally displaced, ZMC fracture remains stable after initial reduction w/ no palpable step deformity at infraorbital rim, minimal changes on orbital volume, globe displacement not evident on CT scan
35
1. When should you do 3-point fixation of zygomatic fractures?
When there is instability of fragments, exploration of orbital floor required
36
1. What is involved in lag screw fixation?
Drill one hole into solid bone with another hole in mobile fragment - allows the screw to engage deeper
37
1. What is involved in wire osteosynthesis?
Wires threaded through and cross fracture site; wire ends bound together → winding joint tips together → reduces fracture, immobilising fracture
38
1. What is involved in the fixation method using titanium plates and screws?
Screw directly into bone across fracture site to immobilise, bicortical screws maintaining plates across fracture line, support until bony healing occurred, choice depends on load required to withstand any overlying tissues to avoid exposure of thick plate over overlying mucosa
39
1. What shape is a zygomatic fracture often present as?
W – inwards
40
1. What can be used to temporarily stabilise the zygomatic fracture?
Urine catheter balloon
41
1. What is the difference between a Bristow and Rowe?
Bristow is a straight elevator and ZMC fracture is lifted laterally and superiorly; Rowe has a different hinge component, hinged handle used to approximate how deep you have entered and to pull so lower blade will do reduction
42
1. How do you perform a pre-op eye examination?
**Basic**: Visual acuity, visual fields, extraocular movements
**Ophthalmology**: Ocular motility test, visual acuity – Snellen chart, pupillary reaction by swinging flash light test , direct light reflex, indirect light reflex, visual field testing, assessment of neurosensory disturbances of infraorbital nerve → 2-point discrimination test
43
1. What is the incidence of SOFS?
0.3-0.8%
44
1. Which nerves are affected in SOFS?
Oculomotor, trochlear, abducent
45
1. What is the treatment of SOFS?
Conservative – observation
46
1. What are the presentations of SOFS?
Ophthalmoplegia, ptosis, proptosis, mydriasis, loss of accommodation, anaesthesia forehead/upper lid, anaesthesia cornea/nose bridge
47
1. What is the incidence of RBH + OCS?
1%
48
1. What are the symptoms of RBH + OCS?
Globe pain, diplopia
49
1. What are the signs of RBH + OCS?
Proptosis, conjunctival chemosis, subconjunctival haemorrhage, tense globe to palpation, reduced visual acuity, sluggish pupil response, relative afferent pupillary defect, ophthalmoplegia
50
How do you manage RBH + OCS?
1. Non-surgical immediate management to reduce pressure in eye – fluid deplete, mannitol, acetazolamide, steroids; surgical – lateral canthotomy, slit in lateral canthus of eye, blunt dissection to relieve pressure within globe
51
1. What type of fracture is a mid-face fracture?
Complex
52
1. What are the simple classifications of mid-face fractures?
Greenstick, open/closed, complicated, comminuted, direct, indirect, orbital, pan-facial
53
1. What happens to the teeth when there is trauma to the mid-face?
Minimal posterior displacement due to intercuspal position but anterior open bite tendency
54
1. In the case of an extreme mid-face trauma where there is downward and backward displacement; why may that be a problem?
This can cause change of architecture of soft palate by pushing it down towards dorsum to tongue → limitation to airway, soft tissue compounded by sub (under) tissues swelling, bleeding within nasopassages of nares
55
1. How do you classify mid-face fractures?
Le Fort
56
1. Why is an anterior open bite possible in LF I fracture?
Because persistent muscle attachment of lateral and medial pterygoids to the pterygoid plates and maxillary tuberosity → tendency to pull segment post + ant → fracture of maxilla → IO haematoma + palatal haematoma → fractured teeth cusps → occlusal discrepancy → AOB
57
1. What type of sound is produced when tapping and upper tooth in a LF I trauma resulting in AOB?
‘Cracked pot’ percussion
58
1. What are the boundaries/bones involved in a LF II fracture?
Entire maxilla, part of nasal bone, lower part of pterygoid plate, nasal septum, palatine bones, dentoalveolar segment, medial 1/3 of orbital rim, inf part of pterygoid plates
59
1. What are the boundaries of a LF III fracture?
Nasofrontal suture, maxillofrontal suture, orbital wall, zygomatic arch + zygomaticofrontal suture
60
1. What type of fracture is involved in a LF III fracture?
Transverse fracture line; Separates both zygomaticomaxillary complexes, Craniofacial distraction; Zygoma, maxilla, palatine bones, nasal bones, nasal septum separated from cranial base; High chance of tear of dura + CSF leak
61
1. How to remove bone using burs
Remove bone w/ round bur to create a narrow gutter MB, avoiding adj roots
Change to fissure bur to deepen gutter cuz you want a narrow rather than wide gutter
For M3M, mostly buccal removed, lingual plate not touched d/t fear of damaging lingual nerve
Stop mesially, don’t kena 7
When cutting, cut from posterior to anterior, use finger rest, retract soft t/s so that soft t/s not caught by shank of bur
62
1. How to remove bone using chisels
Far more destructive → more post op pain and swelling
Lingual split technique → no longer used
63
1. How to raise a triangular flap
Distal reliving incision @ ascending ramus
1 unit length
Pericoronal incision cutting thru alveolar crest fibres including papilla b/w 7 and 8
Mesial relieving incision down from 7 to depth of sulcus
64
1. How to raise an envelope flap
No mesial relieving incision, only distal relieving incision
Ix – pericoronal pathology, e.g. cyst, or x sure how much have to remove
So can extend pericoronal release up to distal of 6
😊 can keep extending if required, just need more sutures at the end
Distal relieving incision @ ascending ramus
Pericoronal incision cutting thru alveolar crest fibres round 8 & extends all around 7
65
1. How to do atraumatic elevation
Free up gingival margin then retract
Use periosteal elevator around gingival margins
Then Howarths / Rake retractor to retract buccal flap
The more traumatic, the most post op pain & swelling
66
1. How to raise a lingual flap
X routinely recommended
But if DA 8, tooth will move into soft t/s → reimpact so possible lingual flap only if clinician is experienced
w/ Howarths / Mitchells / Molt to protect lingual nerve in selected case only
67
1. How to do coronectomy
Remove crown, leave roots in place
If roots are mobile at the time of coronectomy → remove
Consent – plan to coronect but removal may be unavoidable (coronectomy +/- roots removal + risk of infection, migration / risk of lips numbness if doing conventional whole tooth XLA)
68
1. Why avoid unfavourable rotation of apex into IDB
Can depress into canal 🡪 damaging contents of bundle → altered sensation
69
1. Why must flap rest on bone after surgery
To avoid wound breakdown
(flap supported by bone, not sitting on blood clot)
70
1. What is the most important suture for M3M SR
The one placed from buccal tissue to lingual tissue immediately distal to 7
Approximate soft tissue on distal of 7 (mesial papilla on B aspect to DL mucosa behind 7
Encourage good perio health and recovery
71
1. What are the 2 theories for lack of space (causes of canine impaction)
Becker 1981 – loss of guidance plane on lateral incisor (DL), e.g. any interference of the guidance, e.g. peg lateral, absence, traumatised, supernumerary
Peck 1994 – genetic factor – polygenetic, polyfactorial
72
1. How does trauma cause disturbance in tooth germ axis
Leads to dilacerated tooth (root formed at a distinct angle to tooth crown)
Inhibit eruption of tooth completely
73
1. Why does canine impaction lead to resorption of incisor roots
Close relationship with lateral incisor
More likely to be a/w canine that is almost in line of arch (superficial canine – not high in position)
Incidence unknown up to 12.5%
74
1. Why does canine impaction lead to cystic change
Expansion of follicular space → dentigerous cyst
Cyst can change resorption of adj root / overlying bone → eventually perforate thru overlying mucosa & become infected → symptom
75
1. What to do if conservative treatment option is opted and deciduous canine is kept
Primary teeth memang less mineralised
Can be build up to be more bulbous
But primary mmg has short root
So poor crown root ratio ☹
So deciduous tooth appearance might not be satisfactorily in long term
76
1. What are the favourable qualities for exposure and alignment of impacted canine?
Not grossly displaced w/ favourable root morpho
Not too high up cuz too high – long path of eruption
Root morpho – x convergent / divergent / bulbous; conical single has best result
77
1. What are the 2 exposure techniques for impacted canine
Open technique – apical repositioned flap / palatal window
Closed technique – ortho bracket & gold chain → ortho traction activated by orthodontist
78
1. Indications of autotransplantation
Poor pt compliance / limited Tx time desirable
Poorly positioned canine w/ ankylosis – little trauma & in whole
79
1. How to perform autotransplantation
Open apex desirable – some change of re-establishment of blood supply in new position
Need adequate space and bone
Flap same as surgical exposure & removal
Access as for removal but atraumatic elevation avoiding contact w/ PDL / root, tooth parked in t/s whilst prepare socket w/ bur or chisels
Parked = under flap of socket just raised so kept moist but be careful not to accidentally swallow / ingest the tooth
Socket ‘friction fit’ avoiding heat generation
Minimal time \>10mins
May require splint immobilisation
80
1. Outcome of autotransplantation
HIGH failure rate 30% over 9 years d/t poor surgical technique
Internal resorption 🡪 perform RCT post op
External root resorption – particularly if excessive force on tooth in socket
Replacement root resorption, root replaced by bone until exfoliates
Infection
81
1. What’s more important than autotransplantation
Space maintenance w/ cantilever bridge / plate
Evaluate bone level / height – did bone removal in SR compromise the Tx plan? Need grafting?
82
1. Disadvantages of doing apical repositioning flap for incisor exposure
Jeopardises gingival contour when tooth spontaneously aligns
Exposed root 🡪 tooth surface loss & sensitivity once impacted tooth erupts
83
